Process of producing sulfate of ammonia from ammoniacal gases or vapors.



H. KOPPERS.

PROCESS OF PRODUCING SULFATE 0F AMMONIA FROM AMMONIAGAL GASES 0R VAPORS.

APPLIGATION FILED FEB. 4, 1913.

Patented Sept. 16, 1913.

KGP-PERS, "OFlESSEN-UN-EHE RUHR, GERMIAN'Y.

EBRGGESS F .EBRQDIIGING SUILMJJJE 0F AMMONIA-BARON AMMQN-IAGAL GASESQRWMORS.

Specification ofiLetters Patent.

Patented sept. 1.6, 11913.

flpplication file'd Fe'biuary 4,1913. Serial -No. 7463099.

. To all107mmtimely-concern liquor Be it known that I, Hnmnron Koreans,

asuect of the King ofPrussia,andresiding atz29liloltkestrasse,Essen-on-the-Ru'hr Germany, have invented a certain newand use- .fulImproved Process of Producing -Sul-fate of Ammonia from AmmoniacalGasesor Vapors, of which the following is a specificatic-n.

This invention relates to.a novel process of obtaining sulfate ofammonia from ammoniacal gases and vapors, inthe form of a neutral saltwithout .entailing any loss of ammonia.

As is well known, the usual vmethod of producing sulfate of ammonia inbulk consists in either bringing the ammoniacal vgas or the aunnoniacalvapors from ,gas works into intimate contact with sulfuric acid. henmanufacturing in large quantities, however, itis impossible to bring together .the sulfuric-acid and ammonia in that proportion which corresponds with the chemical reaction represented by the equation v 2NH,+HSO (NH 280 The amount of ammonia in the 'gases or vapors varies, and itis impossible to distribute. the sulfuric acid,'even with the aid ofspecial mixing devices, with such exactitude'that each molecule ofsulfuric acid becomes saturated with two molecules of ammonia. In viewof the great danger of free ammonia escaping with the gases and vapors,it is always necessary to make the saturation bothslightly acid in orderthat the whole of the ammonia is retained. There is however, again thepossibility of the prepared salt containing free acid, a. e. of it beingacid. This difliculty is overcome according to the present invention, byretaining an excess of acid at that part ofthe bath where the fresh acidand the mother liquor, separated from the previously formed salt, enterthe same and where the gases and vapors deprived of ammonia leave thebath,

this excess being sufficient to insure that all the ammonia in the gasesis retained with certainty. By introducing the other part of theammoniacal gases or vapor at or close to the place of withdrawal of thesalt, the free acid can be completely neutralized, and a neutral salt beobtained. At this point he ammonia may the accompanying drawing,

heating pipe 12, and

pipe 27.

a o be used in excess,

since the risk-ofloss of ammonia is obviated by an adequateexcess ofacid.

Apparatus suitable for carrying the improved method into effect isillustrated in which shows the apparatus in vertical section.

The saturation vessel 10 is dividedinto .two compartments by a partitionwall 11,

the upper compartment containinga coiled having an inlet pipe 13.Downwardly directed pipes 14 provided with flared, serrated mouths.15,'.depend from-the partition 11, and the months 15 lie somewhat belowthe surface of the saturation bath in the vessel 10. Manholes 16 ,giveaccess 'to the interior of the vessel 1.0. The partition .11 hasatubular neck 17 connecting the lower compartment to the ,gas dischargepipe 18. the neck 17 is a pipe 19,

Passing through which communicates at the top by means of a pipe 20 withthe distilling column 21, and is provided at its lower end with aflared, serrated mouth 22. 'Insidethe pipe .19 is the suction pipe 23 ofan ejector24, said pipe 23 having a bell shaped mouth 25 at its lowerend. Adjacent to the ejector 24 is a centrifugal drier 26, the dischargepipe 27 of which leads back-to the saturation vessel, and discharges bymeans of a plurality of delivery pipes 28, into the saturation vesselclose to the level of liquid therein. Into pipe 27 opens a branch pipe29 through which fresh acid may be introduced into The ammoniacal gasesfrom the retort or oven, having been previously freed from tar andpreferably cooled, pass through the pipe 13 into the saturation vessel10 above the partition base 11, and are there heated by the coiled pipe12. The gases then pass down the tubes 1% and through the months 15 intothe saturatio" batlnwhere the ammonia which they contain is absorbed,the gases then escaping through the central neck 17 to the pipe 18 forfurther use. The ammonia in the gas liquor formed by the previouscooling of the gas is removed in the distilling column 21 by means oflime and steam. The vapors from the column 21 pass through the pipe 20into the inner pipe 19. and through the mouth 22 into thesaturationbath, whereupon after absorption of the annnonia they escapewith the gases through pipe 18. The salt formed accumulates at thebottom of the saturation vessel 10 around the bell 25, and is raised inthe form of a slimy mass by the ejector 24, whence it passes into thecentrifugal drier, by which the mother liquor is separated from thesalt. This liquor flows through pipes 27, 28 into vessel 10 togetherwith the necessary supply of fresh acid-that is introduced into pipe 27through branch 29. The absorption of the ammonia takes place in twostages. Owing to the addition of fresh acid to the mother liquid thatenters the saturation vessel 10 through pipes 28, there exists withinsaid vessel at the corresponding liquid level a certain excess of acid,so that all the ammonia passing said level will be absorbed. As the saltis withdrawn through the bell 25 from the bottom of the vessel 10, theliquid circulates from the top to the bottom; so that the acid lyecontaining salt descends to the part where the ammonia enters from thedistilling column. This saturates the free acid in the lye or salt, sothat the prepared salt is kept as neutral as it possibly can be. Owingto the introduction of an excess of ammonia at this part the ammoniaremains uncombined. This however is not detri-' mental since thisammonia must subsequently pass the acid zone, where it will be combined.

By admitting the retort gases into the saturation bath near its liquidlevel, the important advantage .is obtained that the pressure of thesegases need not be objectionably raised. The pressure of the vaporscoming from the distilling column, however, may be readily increased soas to overcome the pressure existing at the botof a saturation bath inwhich an excess of acid is obtained by the admission of the fresh acid,and separately introducing the remainder of the vapor or gas at anotherpart of the bath where it produces a neutral zone from which the salt-iscontinuously removed.

2. The process of producing sulfate of ammonia, consisting in lntroducmga part -of the ammoniacal gas or vapor near the surface of a saturationbath, where the fresh acid is also added and separately introducing theren'iainder of the vapor or gas into the saturation bath in proximity tothe bottom thereof, where it produces a neutral zone, from which theprepared salt is removed.

3. The process'of producing sulfate of ammonia, consisting inintroducing cooled ammoniacal gas free from tar in proximity to thesurface of a saturation bath, where the fresh acid is also added, theammoniacal liquor separated by the cooling being treated in a distillingcolumn, and the vapors produced therefrom being introduced into thesaturation bath in'proximity to the bottom thereof, where the salt isremoved.

HEINRICH KOP'PERS.

Witnesses:

MAX SOMMER, AUGUST FUGGER.

